Field of the Disclosure
The present disclosure relates to a display device and a method for manufacturing the same.
Description of the Background
With the advancement of the information age, a demand for a display device for displaying an image has been increased in various forms. Therefore, various display devices such as liquid crystal display (LCD) devices, plasma display panel (PDP) devices, and organic light emitting display (OLED) devices have been used.
Among the display devices, the organic light emitting display device is a self-light emitting device, and has advantages in that a viewing angle and a contrast ratio are greater than those of the liquid crystal display (LCD) device. Also, since the organic light emitting display device does not require a separate backlight, it is advantageous that the organic light emitting display device can be fabricated thin and lightweight and has low power consumption. Furthermore, the organic light emitting display device has advantages in that it can be driven at a low direct current voltage, has a fast response speed, and especially has a low manufacturing cost.
However, the organic light emitting display device includes pixels, each of which includes an organic light emitting diode, and has a disadvantage in that the organic light emitting diode may be easily degraded by external factors such as external water and oxygen. In order to prevent this, the organic light emitting display device forms an encapsulation film to prevent the external water and oxygen from being permeated into the organic light emitting diode.
The encapsulation film includes at least one inorganic film and at least one organic film to prevent oxygen or water from being permeated into an organic light emitting layer and an electrode. At this time, at least one organic film generally includes a polymer layer, and is formed by a hardening process after being doped on the substrate in a liquid type. Since such an organic film has flexibility until the hardening process is performed, a problem may occur in that the organic film may overflow outside an area where the encapsulation film is to be formed. To solve this problem, a dam for blocking a flow of the organic film is formed along the outside of the organic light emitting diode.
Meanwhile, when a dam is formed as above, the organic light emitting display device has an uneven surface to be deposited because a step difference is generated by the dam. Therefore, if another layer is deposited on the dam, other problems can occur as follows.
First of all, in the case that the inorganic film forming the encapsulation layer is deposited on the dam, a problem occurs in that it is difficult to form the inorganic film at a constant thickness. Particularly, the inorganic film is formed more thinly in an area where the substrate and the dam are in contact with each other, whereby a crack may occur. The crack may be propagated into the inside along the inorganic film by external impact, and water and oxygen entering the inside along the propagated crack may cause a dark spot and a dark line spot.
Also, in the case that metal patterns are formed on the dam through a process using photoresist pattern, a problem can occur in that metal patterns may not be completely removed from the area where metal should be removed and thus remains as a residual film.